1. Field of the Invention
The present invention relates to aluminosilicate zeolite and especially to a zeolite which is catalytically active and selective in methylation reactions.
2. The Prior Art
A process for the alkylation of aromatic hydrocarbons using a crystalline aluminosilicate zeolite is disclosed in U.S. Pat. No. 4,016,218. The catalyst is modified prior to use in alkylation by a thermal treatment comprising heating the catalyst to high temperatures.
Another process for the methylation of toluene to selectively produce para-xylene is described in U.S. Pat. No. 4,002,698. A phosphorus-modified aluminosilicate zeolite is used which has been activated by vapor phase treatment at a temperature between 752.degree. F. to 1,202.degree. F. for at least 1 hour with a methanol/water mixture.
The methylation of toluene in the presence of a steam treated, aluminosilicate zeolite has been described by Butter et al. in U.S. Pat. No. 3,965,209 which discloses a process for the selective production of para-xylene.
U.S. Pat. Nos. 3,965,207 and 3,965,208 relate to a process for the selective production of para-xylene by reacting a methylating agent with toluene in the presence of an aluminosilicate zeolite having a constraint index of from 1 to 12. Additionally, a Group VA element may be added to the catalyst described in the '208 patent.
A method of reducing the particle size of a crystalline zeolite while substantially maintaining its crystallinity is disclosed in U.S. Pat. No. 3,528,615. The zeolite is heated to an elevated temperature and thereafter the heated zeolite is quenched in a liquid medium.
It is an object of the present invention to provide an aluminosilicate zeolite for use in catalytically promoting the conversion of hydrocarbons.
Another object of the invention is to provide a catalytically active aluminosilicate zeolite that is selective for the production of para-xylene.
Yet another object of the invention is to provide a process for the production of para-xylene using catalysts containing said zeolite.
Still another object of the invention is to provide a process for producing a zeolite.
Other objects and advantages of the invention will be apparent from the following description.